Bacteria release methane and carbon dioxide gases as they break down biomass. the gases are burned to form steam, which turns the turbine to generate electricity.

Biogas is a form of renewable energy source that can be used directly in our homes or can be stored and distributed through transmission lines of an electric power grid.

A biochemical reaction occurs through anaerobic digestion in a large tank called digester. The bacteria are placed in the digester which are fed with wastes like animal manure, kitchen waste and other biodegradable waste. As these bacteria consume these wastes, it gets converted into gases like methane, carbon dioxide, water and hydrogen sulfide. These gases have high calorific vale especially methane (39,820 kJ/kg). This chemical energy is converted into mechanical energy by combusting it through combustion engines. As a result, the mechanical energy is used to turn the turbine which activates the generator.

4- c, because all matter stays the same no matter what. it is still there. 5- b, because matter is known as mass. 6-c because, flammability is a chemical property. malleability is changing the shape of an object.